With diesel engines, particle filters can be used to reduce soot emissions. In such cases a regeneration of the particle filter has to be carried out once it has been filled with soot up to a certain limit, in order to prevent a blockage of the particle filter with the accompanying exhaust gas counter pressure and the risk of an uncontrolled combustion of soot in the filter.
A pressure difference sensor is used in order to enable the blockage of the particle filter with soot to be measured. Said pressure difference sensor measures the pressure difference between the two ends of the particle filter. A high-pressure difference value indicates a high blockage of the particle filter, while a low-pressure difference value is rather a sign of an empty particle filter. Based on the pressure difference value and on the specific engine operating point, a charging value of the particle filter can then be calculated. The charging value can then be used, amongst others, to evaluate the effectiveness of a regeneration, and if necessary further measures can be introduced.
Since there is legislation governing monitoring of the functionality of each component, which directly or indirectly carries out emission-relevant functions, the quality of the pressure difference value has to be monitored continuously. Should the quality of the pressure difference value deteriorate, the quality of the pressure difference value determined in each case will therefore also automatically deteriorate. A deterioration in the pressure difference value can in particular lead to the particle filter being either regenerated too frequently or too seldom. A too frequent regeneration results in an increased fuel consumption and a too seldom regeneration can adversely affect the driving behavior and the emission behavior.